Conventional reflection seismology uses surface sources and receivers to detect reflections from subsurface impedance contrasts in order to obtain data of fluid reservoir information. The obtained image often suffers in spatial accuracy, resolution and coherence due to the long travel paths between source, reflector, and receiver. To overcome this difficulty, a technique commonly known as vertical seismic profiling was developed to image the subsurface in the vicinity of a borehole. By this method, a surface seismic source is placed in the drilling tool, and signals are received by a single downhole receiver or an array of downhole receivers within the same drilling tool. This step is repeated for different depths of the receiver (or receiver array). This method is used for drilling but is also suitable for obtaining fluid reservoir information data in the subsequent production optimising process.
Another known method is to arrange an array of seismic sensors distributed along jointed tubulars (e.g. drill pipe or coiled tubing) to determine the physical condition of the drill string and whether drilling may be optimised. The seismic sensors are configured to detect seismic energy imparted into the adjacent formation by a wellbore source or surface source. This method is used for drilling but is also suitable for obtaining fluid reservoir information data in the subsequent production optimising process.
In addition, an optical fibre can be arranged in the well in order to obtain temperature data of the fluid in the vicinity of the well but not fluid reservoir information data, such as the position and quantity.